CACNA1A and familial hemiplegic migraine: FHM is an autosomal dominant inherited disorder caused by mutations in ion transporters encoding several genes: CACNA1A mutations cause FHM type 1 (FHM1, MIM:141500), ATP1A2 mutations cause FHM type 2, SCNA1 mutations cause FHM type 3 (ICHD-3beta, 2013) [1].